Explanation:
Graphical user interface, application Description automatically generated

The correct display filter for analyzing FTP traffic in a PCAP file is "tcp.port==21". This filter will show all TCP packets where the port number is 21, which is the standard port for FTP control messages.

Data integrity verification involves using tools to compute the message digest of data. A message digest is a cryptographic hash function containing a string of digits created by a one-way hashing formula. This digest, which serves as a unique identifier, can be used to verify the integrity of copied data by comparing it to the original data's digest. If the digests match, it means the data has not been altered, ensuring its integrity.
References: The concept of data integrity and the use of message digests are fundamental security concepts taught in the Understanding Cisco Cybersecurity Operations Fundamentals (CBROPS) course. This course covers the essential skills and knowledge needed to monitor alerts and breaches, and to understand and follow established procedures for response to alerts converted to incidents

Application-level allow list refers to the practice of specifying an index of approved applications that are permitted to be executed in a system environment or network, which means only specific files are allowed while everything else is denied by default, enhancing security.